lib/ext2fs/mkjournal.c

   1 /*
   2  * mkjournal.c --- make a journal for a filesystem
   3  *
   4  * Copyright (C) 2000 Theodore Ts'o.
   5  *
   6  * %Begin-Header%
   7  * This file may be redistributed under the terms of the GNU Library
   8  * General Public License, version 2.
   9  * %End-Header%
  10  */
  11
  12 #include "config.h"
  13 #include <stdio.h>
  14 #include <string.h>
  15 #if HAVE_UNISTD_H
  16 #include <unistd.h>
  17 #endif
  18 #if HAVE_ERRNO_H
  19 #include <errno.h>
  20 #endif
  21 #include <fcntl.h>
  22 #include <time.h>
  23 #if HAVE_SYS_STAT_H
  24 #include <sys/stat.h>
  25 #endif
  26 #if HAVE_SYS_TYPES_H
  27 #include <sys/types.h>
  28 #endif
  29 #if HAVE_SYS_IOCTL_H
  30 #include <sys/ioctl.h>
  31 #endif
  32 #if HAVE_NETINET_IN_H
  33 #include <netinet/in.h>
  34 #endif
  35
  36 #include "ext2_fs.h"
  37 #include "e2p/e2p.h"
  38 #include "ext2fs.h"
  39
  40 #include "kernel-jbd.h"
  41
  42 /*
  43  * This function automatically sets up the journal superblock and
  44  * returns it as an allocated block.
  45  */
  46 errcode_t ext2fs_create_journal_superblock(ext2_filsys fs,
  47                                            __u32 num_blocks, int flags,
  48                                            char  **ret_jsb)
  49 {
  50         errcode_t               retval;
  51         journal_superblock_t    *jsb;
  52
  53         if (num_blocks < JFS_MIN_JOURNAL_BLOCKS)
  54                 return EXT2_ET_JOURNAL_TOO_SMALL;
  55
  56         if ((retval = ext2fs_get_mem(fs->blocksize, &jsb)))
  57                 return retval;
  58
  59         memset (jsb, 0, fs->blocksize);
  60
  61         jsb->s_header.h_magic = htonl(JFS_MAGIC_NUMBER);
  62         if (flags & EXT2_MKJOURNAL_V1_SUPER)
  63                 jsb->s_header.h_blocktype = htonl(JFS_SUPERBLOCK_V1);
  64         else
  65                 jsb->s_header.h_blocktype = htonl(JFS_SUPERBLOCK_V2);
  66         jsb->s_blocksize = htonl(fs->blocksize);
  67         jsb->s_maxlen = htonl(num_blocks);
  68         jsb->s_nr_users = htonl(1);
  69         jsb->s_first = htonl(1);
  70         jsb->s_sequence = htonl(1);
  71         memcpy(jsb->s_uuid, fs->super->s_uuid, sizeof(fs->super->s_uuid));
  72         /*
  73          * If we're creating an external journal device, we need to
  74          * adjust these fields.
  75          */
  76         if (ext2fs_has_feature_journal_dev(fs->super)) {
  77                 jsb->s_nr_users = 0;
  78                 jsb->s_first = htonl(ext2fs_journal_sb_start(fs->blocksize) + 1);
  79         }
  80
  81         *ret_jsb = (char *) jsb;
  82         return 0;
  83 }
  84
  85 /*
  86  * This function writes a journal using POSIX routines.  It is used
  87  * for creating external journals and creating journals on live
  88  * filesystems.
  89  */
  90 static errcode_t write_journal_file(ext2_filsys fs, char *filename,
  91                                     blk_t num_blocks, int flags)
  92 {
  93         errcode_t       retval;
  94         char            *buf = 0;
  95         int             fd, ret_size;
  96         blk_t           i;
  97
  98         if ((retval = ext2fs_create_journal_superblock(fs, num_blocks, flags,
  99                                                        &buf)))
 100                 return retval;
 101
 102         /* Open the device or journal file */
 103         if ((fd = open(filename, O_WRONLY)) < 0) {
 104                 retval = errno;
 105                 goto errfree;
 106         }
 107
 108         /* Write the superblock out */
 109         retval = EXT2_ET_SHORT_WRITE;
 110         ret_size = write(fd, buf, fs->blocksize);
 111         if (ret_size < 0) {
 112                 retval = errno;
 113                 goto errout;
 114         }
 115         if (ret_size != (int) fs->blocksize)
 116                 goto errout;
 117         memset(buf, 0, fs->blocksize);
 118
 119         if (flags & EXT2_MKJOURNAL_LAZYINIT)
 120                 goto success;
 121
 122         for (i = 1; i < num_blocks; i++) {
 123                 ret_size = write(fd, buf, fs->blocksize);
 124                 if (ret_size < 0) {
 125                         retval = errno;
 126                         goto errout;
 127                 }
 128                 if (ret_size != (int) fs->blocksize)
 129                         goto errout;
 130         }
 131
 132 success:
 133         retval = 0;
 134 errout:
 135         close(fd);
 136 errfree:
 137         ext2fs_free_mem(&buf);
 138         return retval;
 139 }
 140
 141 /*
 142  * Convenience function which zeros out _num_ blocks starting at
 143  * _blk_.  In case of an error, the details of the error is returned
 144  * via _ret_blk_ and _ret_count_ if they are non-NULL pointers.
 145  * Returns 0 on success, and an error code on an error.
 146  *
 147  * As a special case, if the first argument is NULL, then it will
 148  * attempt to free the static zeroizing buffer.  (This is to keep
 149  * programs that check for memory leaks happy.)
 150  */
 151 #define MAX_STRIDE_LENGTH (4194304 / (int) fs->blocksize)
 152 errcode_t ext2fs_zero_blocks2(ext2_filsys fs, blk64_t blk, int num,
 153                               blk64_t *ret_blk, int *ret_count)
 154 {
 155         int             j, count;
 156         static void     *buf;
 157         static int      stride_length;
 158         errcode_t       retval;
 159
 160         /* If fs is null, clean up the static buffer and return */
 161         if (!fs) {
 162                 if (buf) {
 163                         free(buf);
 164                         buf = 0;
 165                         stride_length = 0;
 166                 }
 167                 return 0;
 168         }
 169
 170         /* Deal with zeroing less than 1 block */
 171         if (num <= 0)
 172                 return 0;
 173
 174         /* Try a zero out command, if supported */
 175         retval = io_channel_zeroout(fs->io, blk, num);
 176         if (retval == 0)
 177                 return 0;
 178
 179         /* Allocate the zeroizing buffer if necessary */
 180         if (num > stride_length && stride_length < MAX_STRIDE_LENGTH) {
 181                 void *p;
 182                 int new_stride = num;
 183
 184                 if (new_stride > MAX_STRIDE_LENGTH)
 185                         new_stride = MAX_STRIDE_LENGTH;
 186                 p = realloc(buf, fs->blocksize * new_stride);
 187                 if (!p)
 188                         return EXT2_ET_NO_MEMORY;
 189                 buf = p;
 190                 stride_length = new_stride;
 191                 memset(buf, 0, fs->blocksize * stride_length);
 192         }
 193         /* OK, do the write loop */
 194         j=0;
 195         while (j < num) {
 196                 if (blk % stride_length) {
 197                         count = stride_length - (blk % stride_length);
 198                         if (count > (num - j))
 199                                 count = num - j;
 200                 } else {
 201                         count = num - j;
 202                         if (count > stride_length)
 203                                 count = stride_length;
 204                 }
 205                 retval = io_channel_write_blk64(fs->io, blk, count, buf);
 206                 if (retval) {
 207                         if (ret_count)
 208                                 *ret_count = count;
 209                         if (ret_blk)
 210                                 *ret_blk = blk;
 211                         return retval;
 212                 }
 213                 j += count; blk += count;
 214         }
 215         return 0;
 216 }
 217
 218 errcode_t ext2fs_zero_blocks(ext2_filsys fs, blk_t blk, int num,
 219                              blk_t *ret_blk, int *ret_count)
 220 {
 221         blk64_t ret_blk2;
 222         errcode_t retval;
 223
 224         retval = ext2fs_zero_blocks2(fs, blk, num, &ret_blk2, ret_count);
 225         if (retval)
 226                 *ret_blk = (blk_t) ret_blk2;
 227         return retval;
 228 }
 229
 230 /*
 231  * Calculate the initial goal block to be roughly at the middle of the
 232  * filesystem.  Pick a group that has the largest number of free
 233  * blocks.
 234  */
 235 static blk64_t get_midpoint_journal_block(ext2_filsys fs)
 236 {
 237         dgrp_t  group, start, end, i, log_flex;
 238
 239         group = ext2fs_group_of_blk2(fs, (ext2fs_blocks_count(fs->super) -
 240                                          fs->super->s_first_data_block) / 2);
 241         log_flex = 1 << fs->super->s_log_groups_per_flex;
 242         if (fs->super->s_log_groups_per_flex && (group > log_flex)) {
 243                 group = group & ~(log_flex - 1);
 244                 while ((group < fs->group_desc_count) &&
 245                        ext2fs_bg_free_blocks_count(fs, group) == 0)
 246                         group++;
 247                 if (group == fs->group_desc_count)
 248                         group = 0;
 249                 start = group;
 250         } else
 251                 start = (group > 0) ? group-1 : group;
 252         end = ((group+1) < fs->group_desc_count) ? group+1 : group;
 253         group = start;
 254         for (i = start + 1; i <= end; i++)
 255                 if (ext2fs_bg_free_blocks_count(fs, i) >
 256                     ext2fs_bg_free_blocks_count(fs, group))
 257                         group = i;
 258         return ext2fs_group_first_block2(fs, group);
 259 }
 260
 261 /*
 262  * This function creates a journal using direct I/O routines.
 263  */
 264 static errcode_t write_journal_inode(ext2_filsys fs, ext2_ino_t journal_ino,
 265                                      blk_t num_blocks, blk64_t goal, int flags)
 266 {
 267         char                    *buf;
 268         errcode_t               retval;
 269         struct ext2_inode       inode;
 270         unsigned long long      inode_size;
 271         int                     falloc_flags = EXT2_FALLOCATE_FORCE_INIT;
 272         blk64_t                 zblk;
 273
 274         if ((retval = ext2fs_create_journal_superblock(fs, num_blocks, flags,
 275                                                        &buf)))
 276                 return retval;
 277
 278         if ((retval = ext2fs_read_bitmaps(fs)))
 279                 goto out2;
 280
 281         if ((retval = ext2fs_read_inode(fs, journal_ino, &inode)))
 282                 goto out2;
 283
 284         if (inode.i_blocks > 0) {
 285                 retval = EEXIST;
 286                 goto out2;
 287         }
 288
 289         if (goal == ~0ULL)
 290                 goal = get_midpoint_journal_block(fs);
 291
 292         if (ext2fs_has_feature_extents(fs->super))
 293                 inode.i_flags |= EXT4_EXTENTS_FL;
 294
 295         if (!(flags & EXT2_MKJOURNAL_LAZYINIT))
 296                 falloc_flags |= EXT2_FALLOCATE_ZERO_BLOCKS;
 297
 298         inode_size = (unsigned long long)fs->blocksize * num_blocks;
 299         inode.i_mtime = inode.i_ctime = fs->now ? fs->now : time(0);
 300         inode.i_links_count = 1;
 301         inode.i_mode = LINUX_S_IFREG | 0600;
 302         retval = ext2fs_inode_size_set(fs, &inode, inode_size);
 303         if (retval)
 304                 goto out2;
 305
 306         retval = ext2fs_fallocate(fs, falloc_flags, journal_ino,
 307                                   &inode, goal, 0, num_blocks);
 308         if (retval)
 309                 goto out2;
 310
 311         if ((retval = ext2fs_write_new_inode(fs, journal_ino, &inode)))
 312                 goto out2;
 313
 314         retval = ext2fs_bmap2(fs, journal_ino, &inode, NULL, 0, 0, NULL, &zblk);
 315         if (retval)
 316                 goto out2;
 317
 318         retval = io_channel_write_blk64(fs->io, zblk, 1, buf);
 319         if (retval)
 320                 goto out2;
 321
 322         memcpy(fs->super->s_jnl_blocks, inode.i_block, EXT2_N_BLOCKS*4);
 323         fs->super->s_jnl_blocks[15] = inode.i_size_high;
 324         fs->super->s_jnl_blocks[16] = inode.i_size;
 325         fs->super->s_jnl_backup_type = EXT3_JNL_BACKUP_BLOCKS;
 326         ext2fs_mark_super_dirty(fs);
 327
 328 out2:
 329         ext2fs_free_mem(&buf);
 330         return retval;
 331 }
 332
 333 /*
 334  * Find a reasonable journal file size (in blocks) given the number of blocks
 335  * in the filesystem.  For very small filesystems, it is not reasonable to
 336  * have a journal that fills more than half of the filesystem.
 337  *
 338  * n.b. comments assume 4k blocks
 339  */
 340 int ext2fs_default_journal_size(__u64 num_blocks)
 341 {
 342         if (num_blocks < 2048)
 343                 return -1;
 344         if (num_blocks < 32768)         /* 128 MB */
 345                 return (1024);                  /* 4 MB */
 346         if (num_blocks < 256*1024)      /* 1 GB */
 347                 return (4096);                  /* 16 MB */
 348         if (num_blocks < 512*1024)      /* 2 GB */
 349                 return (8192);                  /* 32 MB */
 350         if (num_blocks < 4096*1024)     /* 16 GB */
 351                 return (16384);                 /* 64 MB */
 352         if (num_blocks < 8192*1024)     /* 32 GB */
 353                 return (32768);                 /* 128 MB */
 354         if (num_blocks < 16384*1024)    /* 64 GB */
 355                 return (65536);                 /* 256 MB */
 356         if (num_blocks < 32768*1024)    /* 128 GB */
 357                 return (131072);                /* 512 MB */
 358         return 262144;                          /* 1 GB */
 359 }
 360
 361 int ext2fs_journal_sb_start(int blocksize)
 362 {
 363         if (blocksize == EXT2_MIN_BLOCK_SIZE)
 364                 return 2;
 365         return 1;
 366 }
 367
 368 /*
 369  * This function adds a journal device to a filesystem
 370  */
 371 errcode_t ext2fs_add_journal_device(ext2_filsys fs, ext2_filsys journal_dev)
 372 {
 373         struct stat     st;
 374         errcode_t       retval;
 375         char            buf[SUPERBLOCK_SIZE];
 376         journal_superblock_t    *jsb;
 377         int             start;
 378         __u32           i, nr_users;
 379
 380         /* Make sure the device exists and is a block device */
 381         if (stat(journal_dev->device_name, &st) < 0)
 382                 return errno;
 383
 384         if (!S_ISBLK(st.st_mode))
 385                 return EXT2_ET_JOURNAL_NOT_BLOCK; /* Must be a block device */
 386
 387         /* Get the journal superblock */
 388         start = ext2fs_journal_sb_start(journal_dev->blocksize);
 389         if ((retval = io_channel_read_blk64(journal_dev->io, start,
 390                                             -SUPERBLOCK_SIZE,
 391                                             buf)))
 392                 return retval;
 393
 394         jsb = (journal_superblock_t *) buf;
 395         if ((jsb->s_header.h_magic != (unsigned) ntohl(JFS_MAGIC_NUMBER)) ||
 396             (jsb->s_header.h_blocktype != (unsigned) ntohl(JFS_SUPERBLOCK_V2)))
 397                 return EXT2_ET_NO_JOURNAL_SB;
 398
 399         if (ntohl(jsb->s_blocksize) != (unsigned long) fs->blocksize)
 400                 return EXT2_ET_UNEXPECTED_BLOCK_SIZE;
 401
 402         /* Check and see if this filesystem has already been added */
 403         nr_users = ntohl(jsb->s_nr_users);
 404         for (i=0; i < nr_users; i++) {
 405                 if (memcmp(fs->super->s_uuid,
 406                            &jsb->s_users[i*16], 16) == 0)
 407                         break;
 408         }
 409         if (i >= nr_users) {
 410                 memcpy(&jsb->s_users[nr_users*16],
 411                        fs->super->s_uuid, 16);
 412                 jsb->s_nr_users = htonl(nr_users+1);
 413         }
 414
 415         /* Writeback the journal superblock */
 416         if ((retval = io_channel_write_blk64(journal_dev->io, start,
 417                                             -SUPERBLOCK_SIZE, buf)))
 418                 return retval;
 419
 420         fs->super->s_journal_inum = 0;
 421         fs->super->s_journal_dev = st.st_rdev;
 422         memcpy(fs->super->s_journal_uuid, jsb->s_uuid,
 423                sizeof(fs->super->s_journal_uuid));
 424         memset(fs->super->s_jnl_blocks, 0, sizeof(fs->super->s_jnl_blocks));
 425         ext2fs_set_feature_journal(fs->super);
 426         ext2fs_mark_super_dirty(fs);
 427         return 0;
 428 }
 429
 430 /*
 431  * This function adds a journal inode to a filesystem, using either
 432  * POSIX routines if the filesystem is mounted, or using direct I/O
 433  * functions if it is not.
 434  */
 435 errcode_t ext2fs_add_journal_inode2(ext2_filsys fs, blk_t num_blocks,
 436                                     blk64_t goal, int flags)
 437 {
 438         errcode_t               retval;
 439         ext2_ino_t              journal_ino;
 440         struct stat             st;
 441         char                    jfile[1024];
 442         int                     mount_flags;
 443         int                     fd = -1;
 444
 445         if (flags & EXT2_MKJOURNAL_NO_MNT_CHECK)
 446                 mount_flags = 0;
 447         else if ((retval = ext2fs_check_mount_point(fs->device_name,
 448                                                     &mount_flags,
 449                                                     jfile, sizeof(jfile)-10)))
 450                 return retval;
 451
 452         if (mount_flags & EXT2_MF_MOUNTED) {
 453 #if HAVE_EXT2_IOCTLS
 454                 int f = 0;
 455 #endif
 456                 strcat(jfile, "/.journal");
 457
 458                 /*
 459                  * If .../.journal already exists, make sure any
 460                  * immutable or append-only flags are cleared.
 461                  */
 462 #if defined(HAVE_CHFLAGS) && defined(UF_NODUMP)
 463                 (void) chflags (jfile, 0);
 464 #else
 465 #if HAVE_EXT2_IOCTLS
 466                 fd = open(jfile, O_RDONLY);
 467                 if (fd >= 0) {
 468                         retval = ioctl(fd, EXT2_IOC_SETFLAGS, &f);
 469                         close(fd);
 470                         if (retval)
 471                                 return retval;
 472                 }
 473 #endif
 474 #endif
 475
 476                 /* Create the journal file */
 477                 if ((fd = open(jfile, O_CREAT|O_WRONLY, 0600)) < 0)
 478                         return errno;
 479
 480                 /* Note that we can't do lazy journal initialization for mounted
 481                  * filesystems, since the zero writing is also allocating the
 482                  * journal blocks.  We could use fallocate, but not all kernels
 483                  * support that, and creating a journal on a mounted ext2
 484                  * filesystems is extremely rare these days...  Ignore it. */
 485                 flags &= ~EXT2_MKJOURNAL_LAZYINIT;
 486
 487                 if ((retval = write_journal_file(fs, jfile, num_blocks, flags)))
 488                         goto errout;
 489
 490                 /* Get inode number of the journal file */
 491                 if (fstat(fd, &st) < 0) {
 492                         retval = errno;
 493                         goto errout;
 494                 }
 495
 496 #if defined(HAVE_CHFLAGS) && defined(UF_NODUMP)
 497                 retval = fchflags (fd, UF_NODUMP|UF_IMMUTABLE);
 498 #else
 499 #if HAVE_EXT2_IOCTLS
 500                 if (ioctl(fd, EXT2_IOC_GETFLAGS, &f) < 0) {
 501                         retval = errno;
 502                         goto errout;
 503                 }
 504                 f |= EXT2_NODUMP_FL | EXT2_IMMUTABLE_FL;
 505                 retval = ioctl(fd, EXT2_IOC_SETFLAGS, &f);
 506 #endif
 507 #endif
 508                 if (retval) {
 509                         retval = errno;
 510                         goto errout;
 511                 }
 512
 513                 if (close(fd) < 0) {
 514                         retval = errno;
 515                         fd = -1;
 516                         goto errout;
 517                 }
 518                 journal_ino = st.st_ino;
 519                 memset(fs->super->s_jnl_blocks, 0,
 520                        sizeof(fs->super->s_jnl_blocks));
 521         } else {
 522                 if ((mount_flags & EXT2_MF_BUSY) &&
 523                     !(fs->flags & EXT2_FLAG_EXCLUSIVE)) {
 524                         retval = EBUSY;
 525                         goto errout;
 526                 }
 527                 journal_ino = EXT2_JOURNAL_INO;
 528                 if ((retval = write_journal_inode(fs, journal_ino,
 529                                                   num_blocks, goal, flags)))
 530                         return retval;
 531         }
 532
 533         fs->super->s_journal_inum = journal_ino;
 534         fs->super->s_journal_dev = 0;
 535         memset(fs->super->s_journal_uuid, 0,
 536                sizeof(fs->super->s_journal_uuid));
 537         ext2fs_set_feature_journal(fs->super);
 538
 539         ext2fs_mark_super_dirty(fs);
 540         return 0;
 541 errout:
 542         if (fd >= 0)
 543                 close(fd);
 544         return retval;
 545 }
 546
 547 errcode_t ext2fs_add_journal_inode(ext2_filsys fs, blk_t num_blocks, int flags)
 548 {
 549         return ext2fs_add_journal_inode2(fs, num_blocks, ~0ULL, flags);
 550 }
 551
 552
 553 #ifdef DEBUG
 554 main(int argc, char **argv)
 555 {
 556         errcode_t       retval;
 557         char            *device_name;
 558         ext2_filsys     fs;
 559
 560         if (argc < 2) {
 561                 fprintf(stderr, "Usage: %s filesystem\n", argv[0]);
 562                 exit(1);
 563         }
 564         device_name = argv[1];
 565
 566         retval = ext2fs_open (device_name, EXT2_FLAG_RW, 0, 0,
 567                               unix_io_manager, &fs);
 568         if (retval) {
 569                 com_err(argv[0], retval, "while opening %s", device_name);
 570                 exit(1);
 571         }
 572
 573         retval = ext2fs_add_journal_inode(fs, JFS_MIN_JOURNAL_BLOCKS, 0);
 574         if (retval) {
 575                 com_err(argv[0], retval, "while adding journal to %s",
 576                         device_name);
 577                 exit(1);
 578         }
 579         retval = ext2fs_flush(fs);
 580         if (retval) {
 581                 printf("Warning, had trouble writing out superblocks.\n");
 582         }
 583         ext2fs_close_free(&fs);
 584         exit(0);
 585
 586 }
 587 #endif